Since most of the requirements for the industrial fabric and how to satisfy them can be understood by describing a papermaking fabric on which the most strict requirements are imposed among industrial fabrics, the present invention will hereinafter be described using the papermaking fabric as a representative example.
In a paper making machine, an increase in paper making speed inevitably raises dehydration speed so that dehydration power must be reinforced. Examples of the fabric with good dehydration property include two-layer fabrics having a dehydration hole penetrating from the upper side to the lower side of the fabric. Particularly, a two-layer fabric using a warp binding yarn which is woven with an upper side weft and a lower side weft to constitute an upper side surface design and a lower side surface design is developed with a view to satisfying the surface property, fiber supporting property and dehydration property which a papermaking fabric is required to have.
A two-layer fabric using a warp binding yarn is described in Japanese Patent Laid-Open No. 2004-36052. In the fabric disclosed therein, some warps function as a binding yarn to weave therewith an upper side layer and a lower side layer. At the same time, two warp binding yarns forming a pair constitute a portion of an upper side surface design and a portion of a lower side surface, while complementing each other so that the resulting fabric has excellent surface property and binding strength. According to the design diagram shown in Examples 1 to 3 of Japanese Patent Laid-Open No. 2004-36052, however, since twilled weave in which knuckles formed by the intersection of an upper side warp over an upper side weft regularly and continuously occur in a diagonal direction is adopted, marks in the diagonal direction stand out, which tends to cause wire marks on paper in a diagonal direction. Twilled weave has another problem that twill lines occur continuously in one direction so that a wire is stretched inevitably in the direction of the twill lines when it is used, and the deformation of the wire and meandering attributable thereto occur, resulting in deterioration in the running stability.
With regards to the design of the invention in which a upper side weft pass over three upper side warps and then passes under an upper side warp to form a weft long crimp corresponding to three warps on an upper side, only a ⅓ design in which an upper side warp passes over an upper side weft and then passes under three upper side wefts is described irrespective of twill weave or broken twill weave on pages 15 and 36 in a non-patent document “Seni Kogaku II: Orimono” written by Tatsuo Adachi, published by Jikkyo Shuppan.